Patent Literature 1 discloses a voice input apparatus that has a voice recognition function. This voice input apparatus is configured to receive a voice uttered by a user, to recognize an instruction indicated by the voice of the user (hereinafter referred to as “voice recognition”) by analyzing the received voice, and to control a device in response to the voice-recognized instruction. That is, the voice input apparatus of Patent Literature 1 is capable of performing voice recognition on the voice arbitrarily uttered by the user, and controlling the device in response to the instruction that is a result of the voice recognition (hereinafter referred to as “command”). Hereinafter, an operation of the device using the voice recognition function is referred to as “voice operation”.
The user who uses this voice input apparatus may perform a search on a web site that provides a search service on the Internet (hereinafter referred to as a “search site”), for example, while operating a device such as a television receiver (hereinafter referred to as “television”) and PC (Personal Computer) by using this voice recognition function of the voice input apparatus. Hereinafter, the search by the voice operation is referred to as “voice search”. Data to be searched at this time is classified, for example, into a plurality of categories such as web pages, images, and maps. The user may also use this voice recognition function of the voice input apparatus to search data that belongs to a category different from the above categories, such as program guide data and recorded videos retained in the television.
Patent Literature 2 discloses an information search method for performing information search using a table (correspondence table) that associates keywords with categories. In case that a voice uttered by the user can be classified into either of the categories registered in the table, this information search method allows voice recognition of the voice uttered by the user, and allows a search of the category by using the keyword included in a character string resulting from the voice recognition.
For example, when performing a voice search of the category of “images” for an image of “ABC”, the user who uses the information search method described in Patent Literature 2 may utter “Search images for ABC”. This causes a search site to search the category of “images” for “ABC”. When searching for an image of “XYZ” continuously, the user may utter, for example, “Search images for XYZ”.